JPH03138011A - Method for controlling plate thickness of rolling mill - Google Patents

Abstract

PURPOSE:To control the variation of a plate thickness and to improve the accuracy of the plate thickness and the yield of a product by changing the set values for a rolling down position and a roll speed into values required by the arithmetic interpolation based on what is required by a setup calculation to control the plate thickness. CONSTITUTION:A value interpolated linearly from each set value calculated by using friction coefficients muA and muB when the rolling speed is in the range of VA-VB, a value interpolated linearly from each set value calculated by using friction coefficients muB and muC when the rolling speed is in the range of VB-BC, and each set value calculated by using a friction coefficient muC when the rolling speed is >=VC, are outputted from a computer 7 to a hydraulic rolling reduction controller 6 and a speed controller 5 to be changed to a rolling down position and a roll speed in accordance with each rolling condition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for controlling plate thickness in rolling equipment (continuous rolling mill or reversible rolling mill) for rolling strip-shaped materials such as iron, aluminum, titanium, etc.

[Prior Art] Set-up calculations performed before rolling a strip-shaped material are generally performed according to the procedure shown in FIG. That is, the specifications of the material to be rolled are inputted (Step S1), and the draft schedule, deformation resistance, tension setting value, rolling load, roll reduction position, and roll speed are sequentially calculated (Steps 82 to S6).

[Problem to be Solved by the Invention] However, conventionally, such calculations have been performed in a steady state where rolling is relatively stable (for example, using the friction coefficient μC in Fig. 3), and this calculation When the leading and trailing ends of a strip material are rolled at the determined roll reduction position and roll speed, or when the rolling conditions are changed by increasing or decreasing the rolling speed, the plate thickness fluctuates. This occurs because the roll rolling position and roll speed are not set appropriate for the rolling state.

The present invention aims to solve the above-mentioned problems, and it is possible to perform rolling at a roll reduction position and roll speed suitable for the rolling condition, suppress plate thickness fluctuations due to changes in rolling condition, and reduce plate thickness. The purpose of this invention is to provide a method for controlling plate thickness in a rolling mill that improves accuracy and product yield.

[Means for Solving the Problems] In order to achieve the above object, the method for controlling plate thickness in a rolling mill of the present invention uses friction coefficients in at least two different rolling states during set-up calculations performed in advance before rolling. The set values for the roll reduction position and roll speed are determined in advance, and during rolling, the set values for the roll reduction position and roll speed are determined by interpolation calculation based on those determined by the set-up calculation, according to the actual rolling condition. The feature is that the plate thickness is controlled by changing it to the determined value.

[For production] In the above-mentioned method for controlling plate thickness of a rolling mill according to the present invention.

The set values for the roll reduction position and roll speed for at least two different rolling states are calculated in advance during setup calculation, and during actual rolling, the set values suitable for the rolling state at that time are determined by interpolation and changed. By doing so, variations in plate thickness due to changes in rolling conditions are suppressed.

[Embodiment of the Invention] A method of controlling plate thickness in a rolling mill as an embodiment of the present invention will be explained below with reference to the drawings. Fig. 1 is a block diagram showing a rolling equipment to which the method of this embodiment is applied. , this first
In the figure, STI to STn are rolling stands, 1 is a motor for rotating the work rolls 3 in each rolling stand STI to STn, and 2 is a rolling stand ST1 to S
A belt-shaped material such as iron, aluminum, titanium, etc. is rolled by Tn, 4 is a hydraulic cylinder for adjusting the roll rolling position in each rolling stand STI to STn, and 5 is a hydraulic cylinder for adjusting the rolling position of each rolling stand STI to STn by controlling the motor 3. a speed control device 6 for controlling the roll speed in each rolling stand STI to ST by controlling the hydraulic cylinder 4;
A hydraulic pressure-down control device 7 for controlling the roll-down position at n is a computer that sends set values for the roll-down position and roll speed calculated as described later to each of the control devices 5 and 6.

By the way, in general, the coefficient of friction between the material 2 and the work roll 3 during rolling of the strip material 2 changes depending on the roll speed, as shown in FIG.

In the normally performed set-up calculation, the set values (roll rolling position and roll speed) are set when the rolling speed is sufficiently high (friction coefficient is small), as described above. However, during low-speed rolling, the actual coefficient of friction increases, and if rolling is continued with the set value calculated with a low coefficient of friction, the plate thickness will fluctuate. Therefore,
In the plate thickness control method of the present invention, set values for low-speed rolling conditions are calculated in advance, and when the rolling speed decreases,
By switching to each set value corresponding to this, variations in plate thickness caused by changes in actual rolling conditions are removed.

This example will be described in more detail. In this example, as shown in Fig. 3, low speed (
Consider three cases: VA), medium speed (VB), and high speed (Vc). Before rolling, the set-up calculation described above in FIG. Regarding the friction coefficient μB in the low μ and medium speed (Va) states, the set values for the roll reduction position and roll speed are calculated using the calculator 7.
Calculate and find it. That is, in the case of this embodiment, three sets of set values for the roll reduction position and roll speed are calculated in advance for three different friction states.

Then, during actual rolling, based on the roll rolling position and roll speed in the three friction conditions determined as described above, the most suitable value for the actual rolling condition is interpolated as a set value, and the computer 7 calculates the oil pressure. Settings are output to the reduction control device 6 and the speed control device 5, respectively.

In this example, the rolling state is determined based on the rolling speed. That is, when the rolling speed is within the range of VA-vB, a value linearly interpolated from each set value calculated using the friction coefficients μA and μB, and when the rolling speed is within the range of vB-Vc, the friction coefficient μ, and μC, and when the rolling speed is higher than Vc, each set value calculated using the friction coefficient μC is sent from the calculator 7 to the hydraulic reduction control device 6 and the speed control device 5. By outputting to the roll, the roll rolling position and roll speed are changed according to each rolling state.

As described above, according to the plate thickness control method of this embodiment, even when the rolling speed changes due to changes in rolling speed,
The roll reduction position and roll speed can be maintained appropriately, and fluctuations in plate thickness are suppressed, greatly improving plate thickness accuracy and product yield.

In addition, although the said Example demonstrated the case where the setting value of a roll rolling position and roll speed was calculated|required in three different rolling states, the method of this invention is not limited to this.

In addition, in normal set-up calculations, the dimensions of the strip material,
Although fixed values (constant within one material) are used for hardness, etc., there are fluctuations in specification dimensions, hardness, etc., especially at the leading and trailing ends of the material, and this can make rolling unstable or cause plate thickness fluctuations. It may happen.

Therefore, in order to solve this problem, the dimensions and
By measuring the hardness fluctuation value for each fixed length, performing set-up calculations for each fixed length based on this value before rolling, and changing each set value, a more stable plate thickness can be achieved. Accuracy can also be ensured.

[Effects of the Invention] As detailed above, according to the method for controlling plate thickness of a rolling mill of the present invention, the set values of the roll reduction position and roll speed in at least two different rolling states are set in advance during setup calculation. During actual rolling, by changing the set values suitable for the rolling conditions at that time to values determined by interpolation based on those determined by setup calculations, the roll reduction position and roll speed are determined to be appropriate for the rolling conditions. Rolling is carried out in the same manner, and fluctuations in plate thickness due to changes in rolling conditions are reliably suppressed, which has the effect of improving plate thickness accuracy and product yield.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a rolling equipment to which a method for controlling plate thickness of a rolling mill as an embodiment of the present invention is applied, Fig. 2 is a flowchart showing a general setup calculation procedure, and Fig. 3 is a rolling It is a graph showing the relationship between speed and friction coefficient. In the figure, 1-motor, 2--strip material, 3-work roll, 4-hydraulic cylinder, 5-speed control device, 6-hydraulic reduction control device, 7-computer, and ST1 to STn are rolling stands. Figure 1

Claims (1)

[Claims] In a rolling mill that rolls a strip-shaped material, the set values for the roll reduction position and roll speed are calculated using the friction coefficients in at least two different rolling states during setup calculations performed in advance before rolling. A plate of a rolling mill characterized in that plate thickness is controlled by changing the set values of the roll reduction position and roll speed to values obtained by interpolation calculation based on those obtained by the setup calculation, depending on the state. Thickness control method.